Effect of heteropoly acids on structure, electrochemical behavior, acidic properties and catalytic activity of zwitterionic-type ionic liquid

•Ionic liquid containing HPAs were synthesized and characterized.•Characterization methods are 1H NMR, FT-IR, XRD, SEM/EDX, ICP-OES, BJH and CHNS.•Activity of these catalysts were studied in the synthesis of xanthen derivatives.•Catalysis activity is relative to its acidity and number of acidic sites.•The electronic properties and their electrochemical behavior of the center-metal ions were studied.